Commutator brush assemblies are used on most rotating direct current motors and generators and on a large number of commutating, alternating current motors and generators, which employ segmented commutators to supply or withdraw electric current from such machines. Commutator brush holder assemblies as such are well known to the industry, and are available in a variety of designs and operating characteristics. The following list of United States issued patents are typical of the types of commutator brush holder assembly designs heretofore known and available to the art.
U.S. Pat. No. 2,584,214 entitled "Brush Holder for Electric Motors and the Like" which describes a set of opposed channel-shaped brush holders that cooperate with an insulating backing plate to define a plurality of open ended brush holder tubes. A commutating brush is endwise slidably mounted in each tube with the brushes being pressed to engagement with a commutator ring by a coil spring enclosed by the channel-shaped brush holder tubes.
U.S. Pat. No. 2,984,758 issued May 16, 1961 for a "Electric Motor Brush Holder" describes a combined brush holder and motor housing wherein the brush holder is made integral with the motor housing to facilitate accurate alignment of the brush with the motor commutator.
U.S. Pat. No. 3,316,431 issued Apr. 25, 1967 is for a "Current Collector Contact Means" and describes a brush holder structure for commutator-type electric machines which utilizes wedge-shaped dovetailed and key support means for the brush holders to firmly secure them in place.
U.S. Pat. No. 3,710,159 issued Jan. 9, 1973 for a "Electric Brush and Lead Holder" discloses a combination electric brush and lead holder for electric motors having a spring located therein which urges the associated brush to extend outwardly of the holder in a telescoping fashion and into contact with a machine commutator. The spring is interposed between the inner end of the brush and a disc-shaped terminal end of an electrical lead within the holder structure and is both current carrying and resilient.
U.S. Pat. No. 3,792,298 issued Feb. 12, 1974 for a "Electric Motor Brush Card" in which a planar dielectric support in the form of a card is mounted within a motor housing in a plane disposed perpendicular to the motor armature axis. A plurality of brush holders in the form of rectangular U-shaped insulating members are concentrically arranged on the insulating card about an armature receiving opening defined in the insulating card. The brush holders are of a sheet metal construction of U-shaped cross sectional configuration with open ends and slots defined in the base and leg portions for receiving a brush conductor and portions of a coil tension spring which engages a brush slidably received within the brush holder and biases the brush radially inward into engagement with the armature commutator.
U.S. Pat. No. 3,842,302 issued Oct. 15, 1974 for a "Electrical Snap-In Terminal and Brush Housing and Method of Assembly" which discloses a terminal blade member provided with a plurality of mutually opposed resilient tongues which is used together with a brush housing to compressibly confine a brush biasing means in the form of a coil spring that in turn biases a brush into engagement with the commutator of an electric motor. The terminal blade member is removably secured within the brush housing so as to facilitate changing of worn brushes.
U.S. Pat. No. 3,967,148 issued Jun. 29, 1976 for a "Brush Holder Assembly" in which the brush holder assembly comprises an elongated brush supporting channel having a pair of longitudinal slots in opposite walls thereof and a plate member having wire connectors and retaining catches for holding the plate member in position over a brush. A brush biasing coil spring is supported within the enclosed channel enclosed by the plate member. A plurality of such brush holders may be mounted on a single plate which forms the base of all of the channels, and the plate member is provided with a male terminal tab for receiving the female terminal of a current supply wire.
U.S. Pat. No. 4,311,936 issued Jan. 19, 1982 for a "Brush Holding Device for Electric Motor" describes a brush holding device for an electric motor of small size having a brush cap that is removably mounted to a brush holder so that the brush can be readily replaced. The brush cap is constructed such that a pair of elastic arms axially extend from both sides of a coil retaining portion of the brush cap and includes a vertical wall formed with a keyhole for preventing the brush cap from radial movement and slipping out of the brush holder.
U.S. Pat. No. 4,590,398 issued May 20, 1986 for a "Brush Holder" discloses a brush holder comprising a brush box and a brush terminal. The brush box includes a brush sliding tube within which the brush is slidably supported. The brush terminal has a pair of bent pieces and a central portion therebetween for connecting a pigtail conductor for supply of electric current to and from the brush. A coil spring within the brush sliding tube biases the brush into contact with the commutator of an electric motor.
U.S. Pat. No. 4,855,631 issued Aug. 8, 1989 for a "Brush Holding Device" discloses a brush box formed into tubular shape and having opposite open ends and has a brush slidably supported in a hollow portion thereof. A cap is provided to one end portion of the brush box to block the end portion to provide a reaction force for a coil spring for bringing the brush into sliding contact with a commutator.
While the above-listed prior art devices, and others similar to them, are satisfactory in many respects, they nevertheless require disassembly of substantial parts of the electric machines on which they are used in order to change brushes, or require welding of pigtails to the brush, or other similar characteristics which prevent them from becoming widely accepted, In order to overcome these problems and provide an electric brush holder which allows a technician to easily change the worn brushes of electric machines employing commutators, and also to facilitate final assembly of such machines during manufacture, the present invention was devised.